Child-resistant closures for medicaments have been known in the art for nearly fifty years. These closures generally require two opposed movements acting at the same time to overcome a locking mechanism. For example, one type of child-resistant cap requires a user to squeeze the cap at specific points, causing a deformation, and then to rotate the cap. If either the squeezing or rotating step is not performed, the cap cannot be opened. Another common method for imparting child-resistance on a cap is to require that the cap be pushed in a downward direction and then turned in order to be removed. Again, it can be seen that the two movements are opposed to one another; it is only through application of this unnatural combination of movements that the cap can be removed. Such a cap is disclosed in U.S. Pat. No. 5,316,161. However, when designing child-resistant closures, manufacturers are often forced to dedicate structures of the closure solely to the purpose of creating child-resistance. This results in increased manufacturing and overall packaging costs.
A passive valve is a valve which, in its resting state, is in a closed position, and which only moves to an open position when acted upon by an outside party, substance, or device. However, the passive valve only remains in this open state for the duration of the action by the party, substance, or device; upon cessation of the action, the valve reverts to its closed state. Thus passive valves differ from active valves, which require action by an outside party, substance, or device, to move from the closed position to the open position and further require an additional action to return to the closed position. In this respect, check valves are often considered to be passive valves, as they permit movement in one direction only and are generally found to be closed when no outside forces have been applied to them. Passive valves can therefore be considered “triggerable” in that an outside party, substance, or device “triggers” the valve to move from the closed position to an open position.
Passive or check valves are often of the cantilever, flap or lid variety (e.g., valves in the human heart), and function by mechanical displacement on account of a sufficient overpressure upstream of the valve. The same displacement is, however, not possible in the opposite direction, thus performing the basic function of a valve. Thus, a check-valve is designed to allow for temporal control of fluidic actuation. However, passive valves generally only require movement in a single direction to open the valve. Thus, a passive valve, on its own, would not necessarily impart child-resistance to a closure as a child may be able to trigger the valve to move from a closed position to an open position by simply applying force in a single direction. Thus the use of passive valves in closures for liquid medicaments, while beneficial, does not necessarily meet with industry and government standards for child-resistance, unless additional structures are added to impart child-resistance.
As a result, in light of the foregoing, it is clear that there is an unmet need in the art. Prior art child-resistant closures require an independent construction of all elements needed to impart child-resistance, while triggerable passive valves for the dispensation of liquid medicaments alone fail to create a child-resistant closure. Thus, the prior art required that manufacturers create bulky closures with each part serving a single, specific purpose, and thereby failed to maximize the ease of both manufacture and storage of child-resistant closures for liquid medicaments. The present invention, through its unique combination of features, overcomes the problem and meets the need for providing compact, triggerable passive-valve closures for liquid medicaments, requiring fewer manufactured parts to permit controlled, child-resistant access to the liquid medicament.